I'm actually not surprised about your mum's behaviour. Many psychologists will tell you that when child sexual abuse takes place in a family, it is always with the accomplice of the mother (whether through willful blindness or active encouragement). You will usually find a mother who is weak and ineffectual in the picture, and she is too weak to confront the man out of fear of losing him, so she sacrifices her daughter in order to hold on to the man.
You did nothing wrong my dear, and you should never apologize or feel guilty for reporting him. That was the best thing you could have done for yourself in this life. I am 100% sure that if you had consulted your mother before reporting, she would have turned around and blamed you. She would have shown you her enmity openly as she is showing it to you now. She is a loser who doesn't believe that she can get a man to love her, her low self-esteem is so bad that she is willing to stay with a man who would sexually molest her daugther. It is not your fault that your mum is weak and selfish, it is also not your fault that she can't get a date. It's probably because she has no sense of dignity and pride that she can't get any man to be with her. If she was loving and protective of her own, she would stand a better chance of getting love in this world.
There are many people who never had a loving mum or dad, some grew up with no family at all. But all this doesn't matter, we were never meant to be together with our family forever, at a point we have to strike out on our own. And the sooner this happens the better, those who find independence early and are able to stand on their own two feet without the support of family have a better chance of making it in the real world. So don't feel daunted by the challenges that this life has brought you. It will make you stronger and a more capable individual.
You are not your mum, and you are no longer a victim (and will never be again). Your mum can continue to be who she is and she can continue to play the victim, that's her choice. Even if she loved you once when you were a child, it's obvious that she doesn't have any capacity for love now. Accept that she doesn't love you and learn to give yourself the love and care that you need. If you continue to look for love outside of yourself, you might end up like your mother (a woman so needy of love that she is willing to turn a blind eye to a man molesting her children). It is no wonder that child abuse can run in a family for generations: a girl is molested because her mother fails to protect her as a mother should. She grows up to be needy of love and the protection of a family, so when she finds a man who can provide this she clings to him for dear life. She ends up becoming like her mother (selfish and ineffectual) and lets him molest her children for the fear of losing his love and protection. Her children grow up without love and protection, and the same thing happens generation after generation. But you need to put a stop to the circle of abuse NOW. You need to conquer the longing for love and family that you feel, before it turns you into a slave. Take control of your life and severe all links to the people who don't serve you well anymore. You will find like-minded people who will become your family. Richard Bach once said "The bond that links your true family is not one of blood, but of respect and joy in each other's life".